More than eight out of ten inmates in an open jail are involved in taking, supplying or trading in the Class B drug Spice and legal highs, according to a watchdog report.

The number of inmates using the legal high threatens the stability of Ford open prison, which houses 500 low-risk offenders. In spite of being made illegal in 2009, large numbers of inmates are using Spice and synthetic cannaboids.

“There is a massive amount of Spice and legal highs being used in the prison. The drugs and alcohol recovery team said that they have information leading them to believe